1. Field of the Invention
The invention generally relates to magnetic domain devices and, more particularly, to a package for protecting such devices and for providing integral biasing and in-plane switching magnetic fields for the operation thereof.
2. Description of the Prior Art
As is well understood, magnetic domain devices employing permeable overlay patterns on a ferromagnetic cylindricaldomain-supporting film require a bias magnetic field perpendicular to the substrate as well as a switching magnetic field whose direction may be switched within the plane of the substrate for maintaining and for propagating, respectively, the cylindrical magnetic domains. Previously, all the magnetic domain devices utilized in a given installation were subjected to a single bias field and a single switching field, the latter of which was provided by an orthogonal pair of relatively bulky, relatively large current-carrying coils. The relatively large inductance and power requirements of such switching magnetic field coils present substantial loads to the current driving circuits which control the sequential energization and deenergization of the orthogonal coils and hinder the speed with which this is accomplished. Accordingly, it is desirable that the bulky, high inductance types of switching coils used in the prior art be eliminated and replaced by switching coils having minimum power requirements and permitting high speed current switching. It is further desirable that a self-contained unit be provided including the magnetic domain devices, in-plane switching coil and bias magnetic field means in an extremely dense and low cost package.